INSIDE
INSIDE
----DIRECTOR'S COMMENTS----
Walter Weirich, DVM, PhD
CERF operates as a closed registry with
everything we do aimed at eliminating heritable eye diseases in purebred
dogs. We happily provide the identities of breeding individuals that are
found to be clear, upon request. But, data received on dogs that have
heritable eye disease is released only as pooled data. This has been our
mode of operation from our inception.
As actual gene testing comes on line, whereby carriers as well as affected animals can be identified, new operating philosophies will need to be considered. How do we serve the various breeds satisfactorily to eliminate heritable eye diseases, and yet continue to best serve the breeders of those breeds? Do we release all data to all comers and become an open registry? Or should we continue as a closed registry and merely be a repository of the new data? It would seem pointless to just store the data. It must be used for the benefit of the breed in order to be worth the expense and effort to collect and store it. The breeders confidence in CERF must be protected or the trust and good will that has developed over the years will be lost. So our challenge is to find ways to best use this data and still protect the time, expense and effort that breeders have put into their breeding programs.
There are methods to breed out various traits especially if it is known which dogs have the "bad" gene(s). Even though a "bad" gene may be present the expression of that gene may be modified by proper mate selection. If we carry this to the extreme it could mean that gene therapy will be the method of choice. The costs of these methods will undoubtedly come down, so what I am saying here is well within the realm of possibility in our life times and at reasonable cost.
I point these things out so that we can begin to think about these very important matters. It will not be long until we will have to face these issues. It will be far better if we have at least considered alternatives before we must make the final decision.
----STAFF NOTES----
OptiGen is the new testing facility for our DNA testing on Irish Setters for PRA which detects the rcd1 gene. There has been no change in the way that their testing is handled, however the fees have been reduced from $300/dog to $175/dog. The tests are to still be ordered from CERF with payments being made to CERF. Kits are now to be overnighted to OptiGen. OptiGen is also doing PRA tests on Portuguese Water Dogs to detect the prcd gene. Similar tests are under development for Poodles, Labrador Retrievers, and English Cocker Spaniels. At this time the tests for other breeds of dogs are being handled through OptiGen. If you wish for a change in this or have any comments or suggestions about it please contact their office at 607-257-0301 by phone or genetest@optigen.com by e-mail. You may also want to check out their website at www.optigen.com.
OptiGen is also doing testing on CSNB-Congenital Stationary Night Blindness. At this time the only breed that this test is offered on is the Briards.
Q: What is a "BREEDERS OPTION"?
A: Breeders Option: Entity is suspected to be inherited but does not represent
potential compromise of vision or other ocular function. When the advice is
"Breeder's Option", caution is advised; in time, it may be appropriate to
modify this stand to "No" based on accumulated evidence. If, in time, it
becomes apparent that there is insufficient evidence that an entity is
inherited, it may be deleted from the list.
Q: My dog has a condition noted in one of the categories on the back of the
CERF certificate why was my dog rejected?
A: We still have various guidelines as to diagnoses which are certifiable
in each breed of dog. The categories are there simply to assist the breeders
who have dogs with one of the conditions indicated in the category which is a
"breeders option" in our book. The category system was initiated by the ACVO
genetics committee as a means of assisting owners in breeding away from various
certifiable conditions.
----UPDATES----
CHAMPIONSHIP TITLES
Your CERF certificate may not contain all titles listed on your dogs CERF exam form. This is not a data entry error, so do not be alarmed. Due to spacing limitations some titles may be excluded from your dogs CERF certificate. AKC will still process the information the same as before.
ACVO GENETICS MEETING
Book UpdateThe ACVO Genetics committee is planning on releasing an update to
the 1996 edition of our Ocular Disorders Presumed to be inherited in purebred
dogs, in the summer of 1999. For all of you who have previously purchased the
book, you can look for a notice in the mail informing you that the new
information is readily available. For those who have not yet purchased the
book simply look for the notice of its availability in the next newsletter.
----DX SPOTLIGHT----
There are numerous eyelid disorders in dogs. Entropian (rolling inwards), and ectropian (drooping or rolling outward) are the most common and, although they are considered abnormal eyelid conformations, are characteristics of many breeds. For example, droopy lower eyelids (ectropion) are usually present in Basset hounds and other hound breeds. The breeding of Shar Peis and Chow Chows, in which breeding selection has been made for numerous facial wrinkles, has led to turning in of the eyelids (both upper and lower in many cases).
Ectropian, unless very pronounced, does not lead to severe diseases of the eye itself. However, the droopy eyelid may collect debris such as dust, pollen and plant material from the environment. This may cause ocular irritation that leads to discharge and a red eye. This is particularly pronounced in hunting dogs or dogs that are outdoors much of the time. Dogs that have ectropion must be watched carefully by their owners for possible foreign bodies in their eyes, and the dogs' eyes must be cleaned and often medicated on a regular basis.
Entropion on the other hand frequently causes ocular pain and corneal disease. If the eyelid is rolled inward sufficiently so that the hairs of the eyelid rub on the eye, much damage may be done. Dogs with entropion usually squint and have watery eyes. If the entropion is not corrected and the rubbing continues, ulcers often develop on the cornea and the cornea becomes pigmented. Vision may be lost. Dogs that have had entropion correction surgery cannot be shown.
Although entropion and ectropion are hereditary disorders in many breeds, their mode of inheritance is complex. No one gene controls the development of eyelid conformation. Instead, it is a combination of genes that control eyelid size and shape, depth of the orbit (eye socket), size and shape of the eyes, head conformation and amount of facial skin. All of these genes work in concert to determine the relationship of the eyelids to the eye. Therefore if an eyelid conformation defect is to be eliminated, only those dogs without entropion or ectropin must be bred. In many cases this may be difficult as "abnormal" eyelids may be a desirable breed standard.
The current CERF recommendations for breeding dogs with ectropian is classified as a "breeder option". This is because, although it is a hereditary problem, it is usually not sight threatening. Entropion is a painful and potentially blinding disease and therefore affected dogs in breeds that have a high incidence of entropion (such as Bloodhounds, Chow Chows, English Bulldog, Bull Mastiff, Chinese Shar Pei, Mastiff, Vizsla, and Saint Bernards) are denied certification. (CERF NOTE: As of November 2001, entropion is breeder's option for Bloodhound, Bulldog, Bull Mastiff, Mastiff, Saint Bernards.) However, because exaggerated facial conformation with loose skin and/or heavy facial folds often leads to eyelids that roll in or out predisposed the animal to irritation, discomfort and possible vision loss, selecting away from these traits in all breeds is strongly encouraged.
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